The nginx package in openSUSE contains the thrid-party flood_block module,
which built by default and can not be turned off in the configuration.
The module is the real bottleneck: for every request it connect to
local daemon, write to it, read from it, and closes the connection.
All operations are blocking and during these operations nginx worker
can not handle other requests.
Therefore, you should rebuild your packages, or better, should request
the maintaiter not to build the module by default.
--
Igor Sysoev
http://sysoev.ru/en/